How to recognize a male rat? - briefly
A mature male rat is identified by a markedly longer anogenital distance and visible external testes beneath the tail, appearing as paired swollen sacs. Additional indicators are a broader, rounded abdomen and a prominent preputial gland near the genital region.
How to recognize a male rat? - in detail
Identifying a male rat requires careful observation of physical and behavioral markers. The most reliable indicators are found in the animal’s anatomy and typical actions.
- Anogenital distance: The space between the anus and the genital opening is noticeably larger in males than in females.
- Testes and scrotum: In sexually mature individuals, the testes descend into a visible scrotal sac beneath the tail. The sac appears as a pair of rounded, pinkish bulges.
- Preputial glands: Small, raised glands flank the ventral side of the abdomen, more pronounced in males.
- Urine marking: Males frequently deposit urine droplets on objects to establish territory; females exhibit this behavior far less often.
- Aggressive or dominant behavior: Males tend to display increased aggression, mounting, and wrestling, especially when housed with other rats.
When the animal is young, sexual organs may not be fully developed. In juveniles, the anogenital distance remains the primary visual cue, while the presence of a small, under‑developed scrotum can be felt gently through the skin.
For laboratory or pet settings, a quick examination protocol can be followed:
- Lift the rat gently to expose the ventral surface.
- Measure the distance from the anus to the genital opening; a distance exceeding 1 cm typically indicates a male.
- Palpate the area beneath the tail for a scrotal sac; note any swelling or firmness.
- Observe the rat’s behavior for urine marking or dominance displays over a period of several hours.
These steps provide a systematic approach to sex determination without reliance on external documentation.